Wednesday, February 28, 2007

We spent a great deal of time on Sunday and Monday in the shop at Belfair. I spent most of the time working on a hot wire gear cutter for the large gear.

Lars worked on a number of things, including the super router that has become known as Julie. Originally envisioned as an attachment for a drill press, Julie ended up being constructed with her own motor.

Nephew Gary helped out by building a large nailboard that we call The Devil's Backscratcher or Old Scratch.

Tuesday, February 27, 2007

We showed up early and set up hundreds of pounds of equipment this morning before the 9:00 starting time. We spent the morning carving large slabs of ice off of our block and making a pad of ice upon which we will build our sculpture.

The pad is made of hard-packed snow that has been leveled. After leveling the snow, we dribbled cold water onto it a few times, did some sanding, and eventually got it to the point where we could pour water onto it like a skating rink. By lunch we had a fairly slippery rink and were starting to carve structural pieces out of our slabs. Not a single slab has yet broken!

The giant chainsaw is working flawlessly, as is every other tool. Wow! We look like we sort of know what we are doing!

After a delightfully uneventful flight to Fairbanks, Lars and I spent two days hard at work in the shop at Belfair. We have so many wonderful tools this year! I'll have to post photos of them, but I am unable to at the moment.

At Ice Park today we drew site number 42. Excellent! If you are in Fairbanks, we hope you'll visit us over the next three days. We've already unloaded some equipment at the site, and the rest of our stuff is ready to go in the morning. Our ice block has been oriented and placed (something that didn't happen until the first morning of competition last year), so we are ready to attack the ice with the giant chainsaw at 9:00 AM sharp.

Saturday, February 24, 2007

I checked my email one last time before leaving for a long day of travel only to find a notice telling me that we had been bumped to a much later flight. Our first flight of the day was canceled. Other than the fact that we don't get to join Lars and Sharon for dinner tonight, our new itinerary is actually much better. This change cut our total travel time from thirteen hours down to seven hours, and it pretty much gives us a whole extra day.

Tuesday, February 20, 2007

We've settled on a design and are making last minute preparations for next week's event. I've had a cold for the last few days, so my first priority has been to get healthy; I don't want to head to Fairbanks feeling less than 100%.

Lars has been very busy working on tools. He welded up a new drill press table (the "Drill Press Table X-2007 HD") and has done some ice axle testing. He is also trying to put together a hot tubing ice cutter to try out.

The high temperature in Fairbanks is supposed to be -20°F from today through Sunday, but they say it should be warmer (lows near 0°F) next week.

The word from Ice Alaska is that the ice harvest for the single block has been completed and that the ice this year is 31 inches thick, not counting a little white ice. This is quite a bit thinner than last year's block, but it should be plenty of ice for the music box. Hopefully the cold spell won't crack the ice too much.

Saturday, February 17, 2007

We thought that we would have to resort to building eight or nine hammers, but now we have a design that only requires four hammers, one for each chime. The red thing is a cam that turns clockwise when the crank is turned. Each lobe of the cam lifts the hammer (green) and pawl (yellow), and then releases them in that order. When released, the hammer swings once toward the chime on the left (not pictured) and then swings back toward the cocked position. By the time the hammer returns, the pawl has been released and is able to catch the hammer mostly cocked.

If the crank is turned too fast, the pawl is released in time to catch the hammer after only a fraction of a swing, preventing the hammer from hitting the next lobe on the cam with damaging force. The pawl limits the tempo at which the tune may be played, catches the hammer to prevent damage caused by repeated swinging, and preserves much of the energy of the hammer, making the whole thing more efficient and minimizing wear.

Unfortunately, the pawls are four extra moving parts and an additional axle, but they help us avoid making eight or more moving parts that we would need if we were to use more hammers.

Lars: "I was up in a balloon the other day when the chainsaw store called to tell me that the saw and Handburger Helper Handle was there, but then the balloon came crashing down the next day when they told me that the bar won't fit on the engine! They are '100% positive' that they've got another one that fits it, and can get it up by the 19th, so that's where we are. If that fails, I'm going to demand that they become one of our corporate sponsors, and give us the longest barred saw that they have during the contest in exchange for advertising. Maybe we'll have a corporate sponsor!"

Hopefully they'll get us a chainsaw with a 40 inch or longer bar in time for the competition. If not, we'll have to resort to hot wire slab cutting or cutting the slabs from both sides with a shorter saw like we did last year. We spent too much time trying to align the cuts last year, though. If we have to use that method this year, we'll probably settle for rougher cuts and then smooth the slabs with a large nailboard.

Tuesday, February 13, 2007

Strangely there is not much to report. We continue to work on tools and designs, but our preparations aren't so frantic as they were last year. We have a much better idea of what we are doing this year, a better command of the medium, and more sophisticated tools. Hopefully we aren't victims of false confidence, but, although there is still much to do, there seems to be plenty of time to do it.

I leave for Fairbanks in eleven days, and I only have a few more days before my shipping deadline. I'm taking more stuff with me this year, but that means I'll have less to do in the shop at Belfair after my arrival.

Wednesday, February 07, 2007

Lars writes, "The giant router is tacked together, and needs a little alignment and bit sharpening and final welding, but then it'll be fully ready to use." The router is actually a long, custom attachment for his drill press. The drill press is mounted over a table, and the giant router bit goes through the table and is fixed to a bearing on the under side. It should be great for precision cutting of large machine parts out of slabs of ice.

We're closing in on a final chime design, and much progress is being made on the cam and hammer design, though it is still somewhat up in the air. Before long we might actually know what our sculpture will look like!

Sunday, February 04, 2007

What do you get when you pair architects with minimalist artists and turn them loose on media (snow and ice) they have little or no experience with? The Snow Show is a book filled with wonderful, full-color photographs of the results, creations that are beautiful and interesting enough to more than make up for being somewhat monotonous. Unfortunately, the book also features page after page of uppity, dysfunctional prose. Even the show's web site, with its "this experience is more important than anything else you could possibly be doing" full-screen presentation, manages to express the worst along with the best of the. . . Okay, I should stop now. Get this book for your coffee table and leave it there.

Snow Sculpture and Ice Carving is about as contrasting a book on the subject as could be imagined. A product of 1970's craft culture, James Haskins's book features black and white photos of sculptures that are more accessible if a bit crude. I didn't find the book terribly interesting, however, as it is heavy on ideas for what to carve but light on technique.

Saturday, February 03, 2007

Cam and hammer design has been the topic of much discussion lately. Lars and I both realized that, if we were to simply add extra pins to the cylinder on the original model in order to play all the notes in the tune, several of the pins would end up too close together such that a swinging hammer would crash into an upcoming pin before striking the chime (despite the fact that our tune features no rapidly repeating notes).

A related problem we've begun to consider is that we will have no control over the speed of rotation of the camshaft. There is no way to be certain that someone won't come along and turn the crank much faster than we would prefer. (Computer geeks like me call this an input validation problem.) Even if we have designed the pins so that they don't get clobbered by the hammer when turned at what we think is a reasonable speed, they could still be damaged when someone turns the crank too fast.

Yet another related problem is the speed at which the hammers swing. Since each one is essentially a simple pendulum, increasing the scale from model size means that the period also increases. It wouldn't do to have a hammer take longer to swing to and from a chime than the duration between two repeated notes, and that duration is completely dependent on the whim of the crank turner!

A solution we are likely to try is to use multiple hammers (probably two) for each chime. With only one hammer per chime, we will have repeated notes as little as 0.75 seconds apart, but two alternating hammers would increase the minimum repetition to 1.75 seconds (2.75 if we add a third hammer to the most frequently used chime).

Another solution might be to create some kind of mechanism to prevent the crank from being turned too fast or to prevent the hammers from swinging when it is turned too fast. Lars writes, "Once it gets colder, I might start building machine parts and putting things together at random!"

I went to the hospital cafeteria to see if I could get a bag of ice for a swollen ankle. They didn't have any bags on hand, so they gave me a latex glove to fill. It did the trick! I hurt the ankle by blocking a shot in a hockey game a couple weeks ago. It didn't seem to be healing very well, so I had it looked at. There was a faint line in one of the images, but doc says he doubts it is a fracture. It is a bone bruise that may take a while to fully heal, but I get to keep playing.

Friday, February 02, 2007

Lars has recently made a number of improvements to the ice lathe he made last year. He added legs, a tool rest, and some kind of chucks to hold the workpiece in place. He writes, "the chucks work great! I had to keep tightening them as the piece was turning, since it's above freezing right now. . . . I wore a hockey helmet in case of disintegration."